At the end of his historical account, Mano Singham observes, “The story of the Copernican revolution shows that the actual history of science often bears little resemblance to the popular capsule versions.” In the case of the Copernican revolution, that is particularly true, because the heliocentric model of the solar system, although frequently attributed to Copernicus, is actually from an ancient Greek astronomer, Aristarchus of Samos (circa 310–230 BC). 1
In view of religious criticisms of Copernicus, it is particularly interesting to note that Aristarchus was criticized by Cleanthes the Stoic, who said that Aristarchus should be charged with impiety, as Plutarch wrote, albeit many years later. 2 So not only did Aristarchus anticipate Copernicus, but Cleanthes the Stoic anticipated the criticism of Martin Luther’s lieutenant, Philipp Melanchthon, who, as Thomas Kuhn reports, recommended that severe measures be taken to restrain the impiety of the Copernicans. 3 Most students, before taking a course in astronomy or in the history of science, don’t know about Aristarchus, although they have all heard about Copernicus. Even Stephen Hawking, in A Brief History of Time (Bantam Books, 1988), makes no mention of Aristarchus of Samos.
About 100 years after Aristarchus, Seleucus the Babylonian, a major astronomer of his time, proclaimed that Aristarchus’s heliocentric model was not just hypothetical but true. Seleucus, not unexpectedly, also came in for criticism because he advocated the heliocentric model.
Presentations of the history of astronomy and physics should give more recognition to these pre-Copernican astronomers; otherwise, we are simply perpetuating another myth. It would be more appropriate to emphasize that Copernicus’s great and enduring accomplishment was that he got the heliocentric model moving forward again after it had been held back for 1800 years. Properly highlighting Aristarchus’s contribution also serves to illustrate that science can undergo retrograde motion in its development, as indicated by the enormous length of time the Ptolemaic model held sway, despite the fact that approximately 300 years before Ptolemy, the physically more insightful model of Aristarchus had been proposed.
